Research On Fuel Filling System For LNG Ship Power Engine

For a long time,the shipping industry has made great contributions to invigorate the global economy.With the deepening of economic exchanges between various continents.There is a significant increase in CO2 and nitrogen oxides emitted by the shipping industry.The bad weather brought by the Greenhouse Effect and PM2.5 is getting worse and worse.The International Maritime Organization(IMO)has successively formulated a series of regulations to curb the discharge of pollutants from the shipping industry.LNG-fueled main engine ships have great advantages in reducing pollutant emissions and improving main engine combustion efficiency.The LNG main engine needs the assistance of the LNG fueling system to work.At present,China’s research on the LNG fuel filling system is still in primary stage.During the LNG filling process,the flow,temperature and pressure control are relatively extensive,which makes the LNG fuel main engine combustion efficiency low.In order to protect the environment and improve the efficiency of the LNG fuel main engine,this paper designs a set of low-pressure LNG ship power main engine fuel filling system based on the PLC control system(referred to as low-pressure LNG fuel filling system).First,the piping system design is carried out according to the requirements of gas pressure and temperature of low pressure LNG fuel engine.LNG fuel filling pipe system is mainly composed of LNG filling and storage monitoring system,vaporization and heating unit,combustible gas detection and emergency cut-off system,ventilation and ventilation system,LNG filling pipeline and low temperature accessories.The intermediate medium is used for heat circulation,and the waste heat of the main engine cylinder liner is used to steam and heat the LNG,and the waste heat of the ship is effectively used.Secondly,the PLC hardware design is completed in combination with the control requirements of the low-pressure LNG fuel filling system for the flow,pressure and temperature of LNG and intermediate media.Finally,the system software is designed according to the characteristics of the control system.The low pressure LNG fuel filling process and piping control requirements are analyzed,and the control point table and human-computer interactive control interface are designed by using software such as STEP7 and WINCC.The temperature,pressure and flow rate of LNG and intermediate media are contr olled by PID algorithm.SIMULINK simulation software is selected to simulate the PI contr ol algorithm of the flow control valve in the system.Through parameter adjustment,the val ve regulation PI parameters with accurate adjustment and fast response are obtained.Through the accurate and rapid real-time control of the pipe system by the control syst em,the low-pressure LNG fuel filling system can efficiently and stably output gas with a pr essure of 6Bar and a temperature of 25 ℃ to the LNG fuel engine.